docs: def natural_sort(l, field=None):
      '''
      based on snippet found at http://stackoverflow.com/a/4836734/2445984
      '''
      convert = lambda text: int(text) if text.isdigit() else text.lower()
  
      def alphanum_key(key):
          if field is not None:
              key = getattr(key, field)
          if not isinstance(key, str):
              key = str(key)
          return [convert(c) for c in re.split('([0-9]+)', key)]
      return sorted(l, key=alphanum_key)